1. Field of the Invention
The invention relates to an apparatus for mounting an optical element in an optical system.
More specifically the invention relates to an apparatus for mounting a mirror or a lens in a projection objective of a projection exposure machine in semiconductor lithography.
2. Description of the Related Art
Optical elements, such as mirror and lenses, in optics, in particular in semiconductor lithography, are to be mounted isostatically and therefore in a fashion decoupled in terms of deformation such that disturbances acting from outside as far as possible do not act on the optical element. It is known for this purpose to mount the optical element in an appropriately “soft” fashion. The problem with a soft bearing consists, however, in that sufficiently high natural frequencies are not reached.